<style type="text/css">
  .main-nav > ul > li {
    display: block;
    float: left;
    padding: 10px 6px;
    line-height: 40px;
}
.select_course {
    display: none;
    margin-top: 87px;
    position: absolute;
    top: -30px;
    left: -60px;
    overflow: hidden;
    z-index: 1000;
    text-align: center;
    width: 150px;
    background: rgba(255, 255, 255, 1.0) none repeat scroll 0px 0px;
}
.select_course a {
    background: rgba(255, 255, 255, 0.5) none repeat scroll 0px 0px;
    border-radius: 5px;
    color: #F11222;
    display: block;
    font-size: 16px;
    height: 40px;
    line-height: 40px;
    margin-top: 1px;
    padding: 1px 10px;
    text-align: center;
}
.homeBoxHeader{
    overflow: visible;
}
.homeBoxHeader:after{
    visibility: hidden;
    display: block;
    clear: block
    content:"";
}
</style>
<div class="homeBoxHeader">
  <div class="header">
    <div class="pull-left"> <a href="/"><img src="__PcImages__/ico26.png" style="margin-top:10px; height:40px;
    "></a> </div>
    <div class="pull-right">
      <nav class="main-nav">
        <ul>
          <li><a href="/">首页</a></li>
          <li>|</li>
          <li><a href="<{:U('User/index')}>">个人中心</a></li>
          <li>|</li>
          <li id="xuanti" style="position: relative;">
            <a href="javascript:;">选课</a>
            <div class="select_course">                                    
                <volist name="class_list" id="vo">
                    <a href="<{:U('Index/select_course',array('id'=>$vo['id']))}>"><{$vo['name']}></a>
                </volist>
            </div>
          </li>
          <li>|</li>
          <li><a href="#">手机系统</a></li>
          <li>|</li>
          <li><a href="/">登录</a></li>
        </ul>
      </nav>
    </div>
  </div>
</div>
<script>
    $(function(){
        $("#xuanti").hover(function(){
            $(".select_course").show();
        },function(){
            $(".select_course").hide();
        })
    })
</script>